Vehicle headlamp light distribution control apparatus

Abstract

In a vehicle headlamp light distribution control system which changes a shaded range so as to track a position of a forward vehicle and terminates the tracking when the forward vehicle moves away from the front of a system-mounted vehicle by a tracking limit, how right and left margins of the shaded range for a tracking lag and the tracking limit is determined is arranged to realize adequate dazzle and improve the visibility to a driver of the system-mounted vehicle. It is determined whether the forward vehicle is a preceding vehicle or an oncoming vehicle. When the forward vehicle is the preceding vehicle, optical axis control margins that are right and left margins for the shaded range for the tracking lag are set to be smaller than those when the forward vehicle is the oncoming vehicle to widen the maximum shading range according to the tracking limit.

What is claimed is: 
     
         1 . A vehicle headlamp light distribution control apparatus which controls a light distribution of a headlamp of a vehicle, comprising:
 acquiring means for acquiring preceding/oncoming vehicle information for specifying positional coordinates that are a marked position of a forward vehicle running in front of said vehicle and determining whether the forward vehicle is a preceding vehicle or an oncoming vehicle;   vehicle type determining means for determining a type of said forward vehicle based on the preceding/oncoming vehicle information, as acquired by said acquiring means;   optical axis control margin setting means for setting an optical axis control margin based on a result of determination made by said vehicle type determining means, said optical axis control margin setting means setting the optical axis control margin when said vehicle type determining means determines that the oncoming vehicle is in front of said vehicle to be greater than that when said vehicle type determining means determines that the preceding vehicle is in front of said vehicle;   cut-off line calculating means for, when said headlamp is a left headlamp, defining a location shifted from the positional coordinates of said marked position to the left by said optical axis control margin as a cut-off line of the left headlamp or, when said headlamp is a right headlamp, defining a location shifted from the positional coordinates of said marked position to the right by said optical axis control margin as a cut-off line of the right headlamp based on the positional coordinates of the marked position of said forward vehicle, as acquired by said acquiring means; and   control means for, when said headlamp is the left headlamp, controlling a light-distribution range of the left headlamp so as to shade a right side of said cut-off line or, when said headlamp is the right headlamp, controlling a light distribution range of the right headlamp so as to shade a left side of said cut-off line.   
     
     
         2 . A vehicle headlamp light distribution control apparatus which controls a light distribution of a headlamp of a vehicle, comprising:
 acquiring means for acquiring positional coordinates of a marked position of a forward vehicle running in front of said vehicle;   optical axis control margin setting means for setting said optical axis control margin when the positional coordinates of the marked position, as derived by said acquiring means, are not present in front of said vehicle to be greater than that when the positional coordinates of the marked position are present in front of said vehicle;   cut-off line calculating means for, when said headlamp is a left headlamp, defining a location shifted from the positional coordinates of said marked position to the left by said optical axis control margin as the cut-off line of the left headlamp or, when said headlamp is a right headlamp, defining a location shifted from the positional coordinates of said marked position to the right by said optical axis control margin as the cut-off line of the right headlamp based on the positional coordinates of the marked position of said forward vehicle, as acquired by said acquiring means; and   control means for, when said headlamp is the left headlamp, controlling a light-distribution range of the left headlamp so as to shade a right side of said cut-off line or, when said headlamp is the right headlamp, controlling a light distribution range of the right headlamp so as to shade a left side of said cut-off line.   
     
     
         3 . A vehicle headlamp light distribution control apparatus which controls a light distribution of a headlamp of a vehicle, comprising:
 acquiring means for acquiring positional coordinates of a marked position of a forward vehicle running in front of said vehicle;   optical axis control margin setting means for setting said optical axis control margin when said vehicle is running on a curve to be greater than that when said vehicle is running straight;   cut-off line calculating means for, when said headlamp is a left headlamp, defining a location shifted from the positional coordinates of said marked position to the left by said optical axis control margin as the cut-off line of the left headlamp or, when said headlamp is a right headlamp defining a location shifted from the positional coordinates of said marked position to the right by said optical axis control margin as the cut-off line of the right headlamp based on the positional coordinates of the marked position of said forward vehicle, as acquired by said acquiring means; and   control means for, when said headlamp is the left headlamp, controlling a light-distribution range of the left headlamp so as to shade a right side of said cut-off line or, when said headlamp is the right headlamp, controlling a light distribution range of the right headlamp so as to shade a left side of said cut-off line.   
     
     
         4 . A vehicle headlamp light distribution control apparatus which controls a light distribution of a headlamp of a vehicle, comprising:
 acquiring means for acquiring positional coordinates of a marked position of a forward vehicle running in front of said vehicle;   optical axis control margin setting means for setting said optical axis control margin to be smaller with an increase in speed of said vehicle;   cut-off line calculating means for, when said headlamp is a left headlamp defining a location shifted from the positional coordinates of said marked position to the left by said optical axis control margin as the cut-off line of the left headlamp or, when said headlamp is a right headlamp, defining a location shifted from the positional coordinates of said marked position to the right by said optical axis control margin as the cut-off line of the right headlamp based on the positional coordinates of the marked position of said forward vehicle, as acquired by said acquiring means; and   control means for, when said headlamp is the left headlamp, controlling a light-distribution range of the left headlamp so as to shade a right side of said cut-off line or, when said headlamp is the right headlamp, controlling a light distribution range of the right headlamp so as to shade a left side of said cut-off line.   
     
     
         5 . A vehicle headlamp light distribution control apparatus which controls a light distribution of a headlamp of a vehicle, comprising:
 acquiring means for acquiring preceding/oncoming vehicle information for specifying positional coordinates that are a marked position of a forward vehicle running in front of said vehicle and determining whether the forward vehicle is a preceding vehicle or an oncoming vehicle;   vehicle type determining means for determining a type of said forward vehicle based on the preceding/oncoming vehicle information, as acquired by said acquiring means;   maximum shading range setting means for setting a maximum shading range that is a width between a given controlled center and a cut-off limit position based on a result of determination made by said vehicle type determining means, said maximum shading range setting means setting the maximum shading range when said vehicle type determining means determines that the oncoming vehicle is in front of said vehicle to be smaller than that when said vehicle type determining means determines that the preceding vehicle is in front of said vehicle;   cut-off line calculating means for calculating a cut-off line of said headlamp based on the based on the positional coordinates of the marked position of said forward vehicle, as acquired by said acquiring means; and   control means for determining whether said cut-off line lies in said maximum shading range or not, when said cut-off line lies in said maximum shading range, and said headlamp is a left headlamp, said control means controlling a light-distribution range of the left headlamp so as to shade a right side of said cut-off line or, when said cut-off line lies out of said maximum shading range, and said headlamp is a right headlamp, controlling a light distribution range of the right headlamp so as to shade a left side of said cut-off line.   
     
     
         6 . A vehicle headlamp light distribution control apparatus which controls a light distribution of a headlamp of a vehicle, comprising:
 acquiring means for acquiring preceding/oncoming vehicle information for specifying positional coordinates that are a marked position of a forward vehicle running in front of said vehicle and determining whether the forward vehicle is a preceding vehicle or an oncoming vehicle;   maximum shading range setting means for setting a maximum shading range that is a width between a given controlled center and a cut-off limit position to be smaller with an increase in speed of said vehicle;   cut-off line calculating means for calculating a cut-off line of said headlamp based on the based on the positional coordinates of the marked position of said forward vehicle, as acquired by said acquiring means; and   control means for determining whether said cut-off line lies in said maximum shading range or not, when said cut-off line lies in said maximum shading range, and said headlamp is a left headlamp, said control means controlling a light-distribution range of the left headlamp so as to shade a right side of said cut-off line or, when said cut-off line lies in said maximum shading range, and said headlamp is a right headlamp, controlling a light distribution range of the right headlamp so as to shade a left side of said cut-off line, when said cut-off line lies out of said maximum shading range, said control means placing the light distribution of said headlamp in a low-beam mode.